(1) Field of Invention
The present invention relates generally to a photoreceiver for light-exposure equipment, and more particularly, to a photoreceiver having multiple functions for assembling or reassembling equipment. These functions include automatically detecting, by a kind of photoreceiver, the light-uniform rate of exposure of a light source, perceiving changes in the magnification of a projection lens, calculating the parallel-degree in the moving of two stages, and calculating the focus-position of the projection lens.
(2) Description of Related Art
A conventional photoreceiver is shown in FIG. 1 and is described below.
FIG. 1 is a diagram illustrating the operating system of a conventional photoreceiver. The system includes a first stage 100 that accepts exposed light S1 and seats a mask, an image-forming-second stage 103 in which an image is formed, and an optical detecting part 102 that measures and controls the distribution of the intensity of the exposed light by moving right and left on the second stage 103. The system also includes a source of electric power (not shown).
When the source of electric power is operated by a user, the movement of the conventional photoreceiver according to the above composition begins. When the movement begins, the exposed light S1 comes in through the first stage 100 and forms an image on the second stage 103 through image-forming-lens 101. At the time, the optical detecting part 102 measures and control the distribution of the intensity of the exposed light by moving from left to right and then from right to left on the second stage 103.
In the conventional art, the system performs the following steps to position the work-piece at the focus-point of the projection lens when assembling or reassembling exposure equipment. The system determines the focus-point by repeatedly performing the same process of putting a work-piece at any point, exposing a light source, ascertaining the location of the focus-point by sight after the developing process, moving the work-piece toward the optical axis, exposing the light source again, and ascertaining the location of the focus point by sight after the developing process, etc.
Therefore, when operating an exposure equipment in practice, a work-piece is always located on the focus-point determined by the above process at every exposure time.
However, the conventional photoreceiver has several defects in that it accomplishes only one means to control the rate of exposure intensity as described above to keep it at uniform exposure. In addition, it is only possible to bring it into focus through repeated manual operation.